Ibandronate: A comparison of oral daily dosing versus intermittent dosing in postmenopausal osteoporosis

The objective of this study was to compare efficacy and safety of continuou s versus intermittent oral dosing of ibandronate. Two hundred forty women a ged 55-75 years with postmenopausal osteoporosis were randomized to active treatment or placebo. Similar total doses of ibandronate were provided by t reatment regimens with either continuous 2.5 mg of ibandronate daily (n = 8 1) or intermittent 20 mg of ibandronate every other day for the first 24 da ys, followed by 9 weeks without active drug (n = 78). The placebo group (to tal, n = 81) was crossed over after 12 months to receive either continuous (n = 37) or intermittent ibandronate (n = 35). By 24 months, bone mineral d ensity (BMD) had increased significantly relative to baseline in both activ e treatment groups. The continuous and intermittent groups showed statistic ally equivalent increases in lumbar spine BMD of +5.64% (+/-0.53) and +5.54 % (+/-0.53) and in total hip of +3.35% (+/-0.40) and +3.41% (+/-0.40), resp ectively (per protocol population). Biochemical markers of bone turnover de creased significantly in both treatment groups. The level of marker suppres sion was similar, although the intermittent group displayed, as expected, m ore fluctuation over the treatment period. The frequency of adverse events was similar in the treatment groups. In conclusion, the intermittent and co ntinuous regimens showed equivalent changes in BMD and bone turnover. These results confirm previous preclinical findings indicating that the efficacy of ibandronate depends on the total oral dose given rather than on the dos ing schedule. This supports development of new flexible dosing regimens tar geted to minimize the frequency of dosing, which are expected to improve co nvenience and lead to enhanced long-term patient compliance.